This invention generally relates to water jet apparatus for propelling boats and other watercraft. In particular, the invention relates to mechanisms for braking a water jet-propelled boat or other watercraft.
It is known to provide a mechanism for reversing the direction of the water flow exiting the steering nozzle of a water jet propulsion system. The reverse gate is typically pivotable about a horizontal axis between up and down positions. In the up position, the reverse gate is clear of the water flow exiting the steering nozzle. In the down position, the reverse gate is disposed in the path of the exiting water flow. In its simplest embodiment, the reverse gate has a U-shaped channel which reverses the water flow exiting the steering nozzle.
It would be desirable if a boat or watercraft operator could use the reverse gate as a brake when the boat is moving forward and needs to be stopped quickly. However, in order to accomplish this, what is needed is a system for deploying the reverse gate and then opening the throttle in sequence, both actions occurring in response to the same mechanical operation. Opening of the throttle must be delayed until after the reverse gate has been fully deployed. When the throttle is opened, the engine drives the impeller of the water jet propulsion system, impelling water rearward. The reverse gate in the fully deployed position reverses the flow discharged from the steering nozzle, producing a reverse thrust which causes the forward-moving boat to decelerate.
There is a need for a braking system for a jet-propelled boat or other watercraft which has no electronic components, since electronic components have reduced reliability in aquatic environments.
The present invention is directed to a method and an apparatus for braking a jet-propelled boat. The method in accordance with the preferred embodiments comprises the steps of deploying a reverse gate and then opening a throttle of an engine in response to actuation of a brake pedal. The system in accordance with the preferred embodiments comprises an engine having a throttle, a water jet propulsion system, a reverse gate, a brake pedal, and a mechanical system for deploying the reverse gate and then opening the throttle in response to the brake pedal being actuated by the boat operator. More specifically, the reverse gate is deployed when the brake pedal is moved from a first position to a second position and the throttle is opened as the brake pedal is moved from the second position to a third position. In the preferred embodiment, the brake pedal is pivotably mounted and both movements of the brake pedal are pivoting motions.
The invention is another aspect is directed to a system for actuating a reverse gate. The preferred embodiments of such a system comprise a brake pedal, a brake cable having one end coupled to the brake pedal, a pivotable control lever having a portion coupled to the other end of the brake cable, and an actuating rod having one end coupled to the control lever and the other end coupled to the reverse gate. The system further comprises a spring which does not compress until at least a threshold compressive force is applied which is greater than the load required to actuate the reverse gate. In accordance with one preferred embodiment, the actuating rod is coupled to the control lever via the spring. In accordance with another preferred embodiment, the brake cable is coupled to the control lever via the spring. Once the reverse gate is fully deployed, the actuating rod which actuated deployment is stopped. The spring is designed to allow the brake cable to continue to be displaced after reverse gate deployment. This further brake cable displacement is used to open an engine throttle. This is accomplished using a slave cable which is coupled to the engine throttle and slaved to the brake cable.
In accordance with one preferred embodiment of the invention, the mechanical system linking the reverse gate to the brake pedal comprises a pivotable control lever having a first range of pivoting while the brake pedal moves from the first position to the second position and a second range of pivoting while the brake pedal moves from the second position to the third position. The mechanical system further comprises an actuating rod which displaces in response to the control lever pivoting in the first range and which does not displace during pivoting of the control lever in the second range. The actuating rod is coupled to the reverse gate.
In accordance with another preferred embodiment of the invention, the mechanical system linking the reverse gate to the brake pedal comprises a brake cable having a first range of displacement while the brake pedal moves from the first position to the second position and a second range of displacement while the brake pedal moves from the second position to the third position. In addition, the mechanical system comprises a pivotable control lever which pivots in response to the brake cable displacing in the first range and which does not pivot during displacement of the brake cable in the second range. An actuating rod has one end coupled to the control lever and the other end coupled to the reverse gate.
In accordance with a further preferred embodiment of the invention, the mechanical system comprises: a brake cable having a first range of displacement while the brake pedal moves from the first position to the second position and a second range of displacement while the brake pedal moves from the second position to the third position; a slave cable which is slaved to the brake cable; and a mechanical element which is attached to one end of the slave cable. The mechanical element is coupled to a throttle during displacement of the brake cable in the second range but not in the first range.
In its broadest aspect, the invention is directed to a jet-propelled boat comprising a brake pedal and a reverse gate actuated by the brake pedal. The preferred embodiment further comprises a throttle pedal and an engine throttle actuated by the throttle pedal. In addition, the engine throttle can be actuated by the brake pedal during the braking operation. The preferred embodiments further comprise a mechanical system for actuating the reverse gate in response to actuation of the brake pedal and delaying actuation of the engine throttle until after actuation of the reverse gate. Preferably, the mechanical system comprises a spring arranged so that a compressive force is applied to the spring when the brake pedal is actuated, the spring having a sufficiently high spring rate that the spring does not compress until at least a threshold compressive force is applied via the brake pedal. This threshold compressive force is greater than the load required to actuate the reverse gate. Further, the mechanical system comprises a slave cable which couples the engine throttle to the brake pedal after execution of a range of lost motion.